Objectives: To project the clinical and economic outcomes of a genotype assay for selection of third-line antiretroviral therapy (ART) in resource-limited settings, as per the planned international A5288 trial (MULTI-OCTAVE). Methods: We used the Cost-effectiveness of Preventing AIDS Complications (CEPAC)-International Model to compare three strategies for patients who have failed second-line ART in South Africa: sustained second-line: no genotype assay, all patients remain on second-line ART; A5288: genotype to determine the resistance profile and assign an appropriate regimen; or population-based third-line: no genotype, all patients switch to a potent third-line regimen. Model inputs are from published data in South Africa. Resistance profiles, ART regimens, and efficacy data were those used for trial planning. Results: Projected life expectancy for sustained second-line, A5288, and population-based third-line are 61.1, 103.8, and 104.2 months. Compared to sustained second-line ($12 460), per person lifetime costs increase for the A5288 ($39 250) and population-based ($44 120) strategies. The incremental cost-effectiveness ratio of A5288, compared to sustained second-line, is $7500/year of life saved (YLS), and for population-based third-line, compared to A5288, is $154 500/YLS. In the A5288 strategy, very late presentation to care, coupled with lengthy delays to obtain the genotype, dramatically reduces 5-year survival, making the population-based third-line strategy more attractive. Conclusions: We project that, whereas the public health approach to third-line therapy is unaffordable, genotype assays and third-line ART in resource-limited settings will increase survival and be cost-effective compared to the population-based approach, supporting the value of an efficacy study. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.
